I have been using it on a IPCC Express 3.5.1 system without any problems. It easy to install and uneventfull for us. Upgrading CSA requires a couple of reboots. One to de-install current release and one more after installing the new version of CSA. We run CSA on all our Callmanagers 4.0(1), IPCC, and soon Unity 4.04 servers. We are also using Trend on all the servers.